To reduce the weight of automobiles and meet Corporate Average Fuel Economy (CAFE) standards for carbon emissions, the automotive industry has increasingly substituted aluminum alloys for steel. Aluminum alloys, being lighter in weight, help reduce the overall automobile weight, which reduces fuel consumption. However, the introduction of aluminum alloys creates its own set of needs.
To be useful in automobile applications, an aluminum alloy product must offer the best combination of high strength and other key attributes, such as corrosion resistance, formability, and joining ability. Among different series of aluminum alloys, 7xxx series aluminum alloys are prime candidates for high end strength applications. However, for 7xxx series alloys, an increase in strength typically results in a lowering of the aforementioned key attributes. For example, strength and corrosion resistance performance tend to be inversely related for 7xxx series alloys, meaning that while the alloys have high strength, the corrosion resistance performance is limited.